The hair follicle drug test is becoming more common because it offers significant advantages over urine and mouth swab drug tests.
The most significant advantage is that it’s conducted in plain view. This makes it nearly impossible for an employee to tamper with the sample.
Additionally, because it analyzes the drug metabolites inside the hair shaft, external contaminants or adulterants have absolutely no effect. In other words, you cannot wash your hair to remove evidence of drug use.
Another advantage is that this screening test offers a far longer detection window than the mouth swab or urine drug testing.
How does this test work?
This testing method can be conducted literally anywhere because no fluid samples are collected and no privacy is required.
During the collection process, a specialist will first review identifying information of the test subject. They will then use a pair of scissors to collect approximately 100 strands of hair from the the test subject’s head. If there are concerns that taking the hair specimen will leave an empty or bald-looking patch, several samples can be collected from multiple locations.
The hair specimen, which is typically about 1.5 inches long, must be collected from as close to the surface of the scalp as possible to enable the laboratory to identify recent drug use. While technically drug use can be identified throughout the entire sample, we are usually most interested in the 90 days prior to the test, so the end of the strand will usually be discarded and only a short section of the base will be used for testing.
Once the hair specimen is collected, it is placed in a tamper-proof plastic bag and sent to the lab for testing. During testing, specific substances in the proteins of the hair follicle are measured. The cortex of hair strands stores deposits that remain in the body after a drug has metabolized in the system.
This testing method is popular among employers because it provides an in-depth look at the prior drug-related behavior of potential job candidates or employees.
- Offers a longer detection window than other drug test types
- Shows historical drug use behavior
- Almost impossible to manipulate by the drug user
- Detects drugs that metabolize quickly, such as cocaine
- Taken most seriously be test takers, which can deter candidates who know they will not pass
- Works even on people with no head hair because body hair can also be used
- Can be a little more costly than a urine drug test
- Results can take a little longer to obtain
- Not a good way to test for impairment or very recent drug usage
- Not an approved method for the DOT drug testing
Drugs that can be identified?
A hair drug test can detect various legal and illegal substances, within a window of a few days after drug use up to 90 days, including, but not limited to:
- Opiates / opioids
- Synthetic marijuana
- Ecstasy (MDMA)
- Crystal meth
- Rohypnol (roofies)
Are there scenarios where it cannot be used?
There are certain scenarios when a hair follicle drug test cannot be used, which is a major limitation in areas other than pre-employment screening. Because it can take time for the drugs used to show up in the hair, the hair has to grow beyond the scalp to show results. In other words, you would not be able to take a hair sample from someone who used methamphetamine for the first time today or yesterday and see that they used the drug. It would typically take five to seven days for the hair to grow enough for the drug to show up as a positive result.
DOT drug testing
This method is not currently accepted by the Department of Transportation for DOT drug testing. However, they do have plans to implement this method due to it’s significantly longer detection window. Therefore, if you would be testing an employed driver after an accident on the job, a hair drug test would not suffice as evidence of whether the driver was under the influence. Even still, hair follicle tests can be highly effective for employers who hire drivers and operators for thorough pre-hiring screening.
It is often assumed that if a person has no hair on their head, this method worn’t work, but this is not the case, because body hair can also be used as a sample. However, the rate of body hair growth is varied greatly compared to head hair growth, so the results of the test can be a little less reliable or a little less in-depth. Additionally, hair drug tests can be performed no matter what type of treatment their hair has undergone. Therefore, if a person’s hair has been chemically treated with perming agents, dyes, or other styling products, it will not affect the outcome of the test results.
Overall, this is the most effective and comprehensive methods for determining whether your employees or prospects have used drugs.